Safety Latch for a Multifunction Scaffold

ABSTRACT

A lightweight, multifunction scaffold comprises first and second ladder frames, and an adjustable height platform configured to be supported between the first and second ladder frames at a user selected height in an adjustment range. The adjustable height platform comprises a pair of spaced-apart side rails extending between the ladder frames and a deck supported on opposing sides by the side rails. The deck includes at least one recess in a top surface of the deck adjacent each of the opposing sides of the deck. The scaffold further includes at least one latch rotatably mounted to each side rail and including a catch element for engagement with the recess in the top surface of the deck to secure the deck on the side rails. The latch is movable between a disengaged position allowing the deck to be installed or removed from the side rials and an engaged position in which the catch element extends over a top surface of the deck and engages with a respective one of the recesses in the deck so that the catch element is flush with or below the surface of the deck.

TECHNICAL FIELD

The present disclosure relates generally to lightweight scaffolding and,more particularly, to a lightweight, multi-function scaffold.

BACKGROUND

Lightweight scaffolds made from metal tubing are commercially availablefor use when working close to the ground. One such scaffold comprises anadjustable height platform supported between two ladder frames. Theplatform includes two side rails with guide channels at each endthereof, and a deck that is supported by the side rails. The guidechannels slide up and down along the vertical supports of the ladderframes to allow the height of the platform to be adjusted.

The deck of the platform rests on the side rails on either side of thedeck and is held in place by a spring-biased latch that pushes the deckdown against support surfaces on the side rails. In a conventionalmulti-function scaffold, the latch comprises an L-shaped pin mounted tothe side rail that rotates out of the way while the deck is being putinto place, and then rotates back after the deck is in place so that thelatch extends over the top surface of the deck to prevent the deck fromlifting off of the side rails.

There are some drawbacks with the current latch design. Because thelatch extends above the top surface of the deck, it presents a trippinghazard to workers standing on the deck. Also, a worker may accidentallykick and disengage the latch holding the deck in place. If the latchbecomes disengaged, the deck may shift and/or dislodge causing theworker to fall.

Accordingly, there is a need for a new design for the latch thateliminates these safety hazards.

SUMMARY

The present disclosure provides a lightweight, multifunction scaffoldwith an improved safety latch. The scaffold comprises first and secondladder frames, and an adjustable height platform configured to besupported between the first and second ladder frames at a user selectedheight in an adjustment range. The adjustable height platform comprisesa pair of spaced-apart side rails extending between the ladder framesand a deck supported on opposing sides by the side rails. The deckincludes at least one recess in a top surface of the deck adjacent eachof the opposing sides of the deck. The scaffold further includes atleast one latch rotatably mounted to each side rail. Each ladder frameincludes a catch element for engagement with a respective recess in thetop surface of the deck to secure the deck on the side rails. Thelatches are movable between a disengaged position allowing the deck tobe installed or removed from the side rials and an engaged position inwhich the catch element extends over a top surface of the deck andengages with a respective one of the recesses in the deck so that thecatch element is flush with or below the surface of the deck.

The seating of the latch in the recesses on the top surface of the deckeliminates a trip hazard inherent in conventional designs. Further, therecessing of the latch prevents the worker from accidentally kicking anddisengaging the latch while standing on the platform. As a result, thepossibility of the deck shifting or being dislodging is reduced, thusreducing the risk of a fall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a multi-function scaffold including twoladder frames and an adjustable height platform according to a firstembodiment.

FIG. 2A is a side view of the scaffold with the platform in a normalorientation and adjusted to a top of the ladder frame.

FIG. 2B is a side view of the scaffold with the platform in an invertedorientation and adjusted to bottom of the ladder frame.

FIG. 3 is a partial perspective view of a side rail assembly including aside rail and guide channel for the adjustable height platform.

FIGS. 4A and 4B are section views of exemplary side rails for theadjustable height platform according to the first embodiment.

FIGS. 5A and 5B are a partial top plan views of the platform showing thelatch in disengaged and engaged positions respectively.

FIGS. 6A and 6B are partial perspective views illustrating methods ofattaching casters to the ladder frame.

FIG. 7 is a perspective view of the multifunction scaffold with anadjustable height platform according to a second embodiment.

FIG. 8 illustrates one of two side rail assemblies of the adjustableheight platform according to the second embodiment.

FIG. 9 is a partial section view of a side rail according to a secondembodiment.

FIG. 10 is a partial top view of a side rail showing the configurationof the slots in the side rails of the adjustable height platform.

FIGS. 11 and 12 are perspective view of a latch for securing the deck ofthe adjustable height platform.

FIG. 13 is a partial perspective view illustrating the installation ofthe latch.

FIGS. 14A and 14B are a partial top plan views of the platform showingthe latch in disengaged and engaged positions respectively.

DETAILED DESCRIPTION

Referring now to the drawings, FIG. 1 illustrates a multi-purposescaffold 10 according to an exemplary embodiment. The multi-purposescaffold 10 comprises two ladder frames 12 and an adjustable heightplatform 20 supported between the two ladder frames 12. As described ingreater detail below, the adjustable height platform 20 can be mountedbetween the ladder frames 12 in two different orientations depending ona height requirement for a task. The first orientation shown in FIG. 2Aenables the platform 20 to be adjusted to its maximum height. The secondorientation shown in FIG. 2B enables the platform 20 to be adjusted toits minimum height. The first orientation is for relatively greaterheights, i.e., farther from the ground, and the second orientation isfor relatively lower heights, i.e., closer to the ground.

Each ladder frame 12 comprises two vertical supports 14 connected by twoor more cross members 16 that serve as ladder rungs. The verticalsupports 14 and cross members 16 are preferably made of a metal tubingor other tubular material. The cross members 16 are preferably welded ateach end to respective ones of the vertical supports 14 so that eachladder frame 12 is a unitary structure.

A series of aligned openings 18 extend through the vertical supports 14perpendicular to the plane of the ladder frame 12 and are spaced 2inches apart. As will be hereinafter described in more detail, theopenings 18 are engaged by a releasable locking mechanism 30 on theplatform 20 to secure the platform 20 at a desired height between theladder frames 12. Additionally, openings 18 a extend transverselythrough the lower end of each vertical support 14. These opening 18 aare used to secure casters 50 to the vertical supports 14 when the siderail 20 is in the lowermost position as will be hereinafter described.

The platform 20 comprises two side rail assemblies 21 that extendbetween the ladder frames 12 and a deck 40 that is supported by the siderail assemblies. Each side rail assembly 21 comprises a side rail 22 andtwo guide channels 24 at opposing ends of the side rail 22. The siderails 22 are configured to provide a support surface for the deck 40 intwo orientations, referred to herein as the normal orientation andinverted orientation. Two variations of the side rail 22 are shown inFIGS. 4A and 4B respectively. In both cases, the cross section of theside rail 22 is symmetrical about a horizontal plane H.

In the embodiment shown in FIG. 4A, the side rail 22 comprises agenerally C-shaped channel with a central web 22 a two parallel flanges22 b. Stiffening flanges 22 c extend outwardly from the outer ends ofthe parallel flanges 22 b. In this embodiment, one parallel flange 22 bprovides a support surface for the deck 40 in the normal orientation andthe other parallel flange 22 b provides a support surface for the deck40 in the inverted orientation.

In the embodiments shown in FIG. 4B, the side rail 22 comprises agenerally C-shaped channel 22 with a central web 22 a and two parallelflanges 22 b as previously described with two additional channels 22 dattached to the outer ends of the parallel flanges 22 b. Like theprevious embodiment, the parallel flanges 22 b function as supportsurfaces for the deck 40 in the first and second orientationsrespectively. The additional channels 22 d provide greater strength andrigidity compared to the design in FIG. 5A.

The side rails 22 are equipped with latches 42 to hold the deck 40 downonce the deck 40 is put in place. The latches 42 are mounted to theparallel flanges 22 b of the side rail 22 and are configured to projectup through slots 40 a in the deck 40. The latches 42 include a catchelement 46 connected to a spring-biased latch pin 44 that pulls thecatch element 46 down into contact with the top surface of the deck 40.The latch pin 44 with the attached catch element 46 is rotatable.

To secure the deck 40 in place, the latch 42 is rotated so that thecatch element 46 can pass through the slot 40 a in the deck 40 while thedeck 40 is being lowered into place as shown in FIG. 5A. Once the deck40 is in place, latch pin 44 is pushed upward and then rotated 90degrees so that the catch element 42 extends over and engages the uppersurface of the deck 40 as shown in FIG. 5B. The latch pin 44 is biasedby a spring 48 so that when the latch pin 44 is released, the catchelement 46 presses the deck 40 down against the support surface, thuspreventing the deck 40 from lifting up off the side rail 22. The topsurface of the deck 40 includes a recess or counter-sink 40 b into whichthe catch element 46 seats so that the catch element 46 is flush with orbelow the top surface of the deck 40. Providing a recess 40 b in the topsurface of the deck 40 for the catch element 46 reduces the trippinghazard and further reduces the likelihood that the catch element 46 willbe accidentally kicked and disengaged.

Referring back to FIG. 3 , the ends of each side rail 22 connectdirectly or indirectly to a C-shaped guide channel 24 sized to fitaround the vertical supports 14 of the ladder frames 12. In oneembodiment, a square sleeve 23 is interposed between each end of theside rail 22 and the guide channel 24 for mounting a safety rail to theplatform. The sleeve 23 is configured to receive posts P of the safetyrail (not shown), which can be secured to the sleeve 23 by latches (notshown). In one embodiment, the side rail 22, sleeves 23 and guidechannel 24 s for each side rail assembly are welded together to form aunitary structure.

The guide channels 24 comprises a C-shaped channel and are configured toslide along the vertical supports 14 of the ladder frames 12 at each endof the scaffold 10 to adjust the height of the platform 20. Two openings26 are formed in the inner flanges of each guide channel 24 for lockingthe guide channel 24 at a selected height as hereinafter described. Theopenings 26 are spaced to align with the openings 18 in the verticalsupports 14 of the ladder frame 12 at preselected heights. The openings26 in the guide channels 24 are engaged by a releasable lockingmechanism 30 (described below) on the platform 20 to secure the platform20 at a desired height between the ladder frames 12. A third opening 28is formed near a lower end of the guide channel 24 and aligns with anopening 18 in the vertical support 14. A latch 29 passes through alignedopening 28 and 18 in the guide channel 24 and vertical support 14respectively. The latch 29 serves as a failsafe and provides additionalsafety in case the locking mechanism 30 inadvertently disengages.Diagonal braces 25 connect a lower end of each guide channel 24 to theside rail 22 to increase the strength and rigidity of the assembledscaffold 10. The increased stability enhances worker's confidence whenstanding on the scaffold.

Each guide channel 24 includes a releasable locking mechanism 30 forlocking the platform 20 at a desired height. In one embodiment, thereleasable locking mechanism 30 comprises a U-shaped latch 32 thatengages with the aligned openings 26 and 18 in the guide channel 24 andvertical supports 14 respectively to lock the side rail 22 at a desiredheight. Each latch 32 includes a pair of spaced apart legs 32 aconnected by a cross member 32 b. A bracket 34 supports the latch 32.The bracket 34 includes a pair of openings 36 through which the legs 32a of the latch 32 extend. Springs 38 surrounding each leg 32 a of thelatch 32 and bias the latch 32 to a locked position. The springs 38 arecompressed when the latch 32 is pulled back to disengage the latch 32and push the latch 32 back to an engaged position when the latch 32 isreleased.

In some embodiments, the scaffold 10 includes casters 50 disposed at thelower end of each vertical support 14 as shown in FIGS. 6A and 6B. Eachcaster 50 includes a stem 52 that extends into the lower end of avertical support 14. The stem 52 is sufficiently long to overlap atleast two openings 18 in the lower end of the vertical support 14. Thestem 52 of the caster 50 includes an opening 54 that is located to alignwith an opening 18 in the vertical support 14 when the stem 52 of thecaster 50 is inserted into the vertical support 14. A latch 56 passesthrough aligned openings 54 and 18 in the caster 50 and vertical support14 respectively to secure the caster 50 to the vertical support 14.

In the embodiment shown in FIG. 6A, the stem 52 further includes asecond opening 58 oriented 90 degrees relative to the first opening 54.The second opening 56 is for use when the platform 20 is adjusted to theminimum height as shown in FIG. 2B. In this case, the obstruction of theguide rail 20 prevents insertion of the latch 56 through the alignedopenings 54 and 18 in the caster 50 and vertical support 14. In thiscase, the second opening 58 aligns with opening 18 a in the verticalsupport and an opening 27 in the guide channel 24 of the side rail 20 sothat the latch 56 can be inserted through the aligned openings 58, 18 aand 27 to secure the caster 50 to the vertical support 14.

FIG. 6B shows an alternate embodiment, where the caster 50 includes asingle opening 54 as previously described. In this embodiment, theopening 18 a in the vertical support 14 is vertically aligned with anopening 18. In this case, the caster 50 can be turned 90 degrees so thatthe opening 54 aligns with opening 18 a in the vertical support and theopening 26 in the guide channel 24 of the side rail 20 when the siderail is in the lowermost position as shown in FIG. 2B

In some embodiments, the casters 50 can be replaced by footpads, leveljacks or socket levelers (not shown) or other ground-engaging member.comprising a generally flat pad that contacts the ground or underlyingsurface and a stem that extends into that extends into the lower end ofa vertical support 14.

Additional details of the first embodiment of the multi-functionscaffold are described in co-pending U.S. patent application Ser. No.17/537,163 which is incorporated herein in its entirety by reference.

FIG. 7 illustrates another embodiment of a multi-function scaffold 10with two ladder frames 12 and an adjustable height platform 20 supportedbetween the two ladder frames 12. As with the first embodiment, theadjustable height platform 20 can be mounted between the ladder frames12 in two different orientations depending on a height requirement for atask. The first orientation enables the platform 20 to be adjusted toits maximum height. The second orientation enables the platform 20 to beadjusted to its minimum height.

The ladder frames 12 are the same as the first embodiment and thedescription of the ladder frame 12 is omitted for the sake of brevity.It is also noted that similar reference numbers are used in FIGS. 7-14to indicate similar components.

The platform 20 comprises two side rail assemblies that extend betweenthe ladder frames 12 and a deck 40 that is supported by the side railassemblies. An example side rail assembly 300 is shown in FIG. 8 . Inthis example, each side rail assembly 300 comprises a side rail 22 andtwo guide channels 24 at opposing ends of the side rail 22. The siderails 22 are symmetrical about a horizontal plane and configured toprovide a support surface 22 a for the deck 40 of the platform 20 inboth a first orientation (guide channels extending down from side rail22) and a second orientation (guide channel extending up from side rail22). The platform 20 can be used in either orientation. The ability toreverse the platform 20 extends the range of adjustment, increases themaximum height and decreases the minimum height.

The guide channels 24 comprises a C-shaped channels 24 and areconfigured to slide along the vertical supports 14 of the ladder frames12 at each end of the scaffold 10 to adjust the height of the platform20. Each guide channel 24 includes a releasable locking mechanism 30 forlocking the platform 20 at a desired height. In one embodiment, thereleasable locking mechanism 30 comprises a U-shaped latch 32 thatengages with the aligned openings and in the guide channel 24 andvertical supports 14 respectively to lock the side rail 22 at a desiredheight. The U-shaped latch 32 is biased by springs to an engagedposition. To adjust the height of the platform, the latch is pulled backto disengage the latch from the holes 18 in the vertical supports 14.Once disengaged, the platform 20 can be adjusted in height to anydesired position in the adjustment range. When the platform 20 isadjusted to the desired height, span pins 34 can be inserted throughholes in the guide channel 24 that align with the holes 18 in thevertical supports 14 as a failsafe. The span pins 34 secure the platform20 at the desired height even if the releasable locking mechanism failsor disengages.

The side rails 22 in the second embodiment are equipped with removablelatches 42, also referred to as locking pins 42, to hold the deck 40down once the deck 40 is put in place. FIG. 9 shows the side rails 22with the deck 40 and latches 42 installed. The installation of the latch42 is the same in both orientations of the platform 20. Thecross-section of the side rail 22 is the same as shown in FIG. 4B.

As shown in FIGS. 10 , specially formed slots 23 are formed in the outersurfaces 22 b of the side rail 22. The slots 23 in the outer surfaces 22b are vertically aligned. As explained in more detail below, the latches42 can be installed in the vertically aligned slots 23 in both the firstand second orientations. The slots 23 each include a channel 23 a,depicted in FIG. 5 as an elongated narrow section of the slot 23. Theslots 23 each also include a large hole 23 c formed near one end of thechannel 23 a and a smaller hole 23 b formed near the opposing end of thechannel 23 a. The holes 23 b, 23 c located along the length of thechannel 23 a facilitate installation of the latch 42 as hereindescribed. When a need arises to reverse the platform 20, the latches 42can be removed and re-installed in the new orientation without use ofany tools. This eliminates the need to have separate latch mechanismsfor use in each orientation.

The design of an example latch 42 is shown in FIGS. 11 and 12 . Thelatch 42 comprises a shaft 44 and a catch element 46 that is press fitand/or spot welded onto one end of the shaft 44. The shaft 44 includes areduced diameter section 44 a near the end on which the catch element 46is installed and a pair of spaced opening 44 c to receive respectiveroll pins 44 b, each of which forms one or more protrusions on the shaft44. The catch element 46 has a generally circular shape with a flat onone side, i.e. a D-shape. Additionally, the catch element 46 includesintegral detents formed by stamping on the underside thereof to engagein the slots 23 as hereinafter described. When the latch 42 isinstalled, a biasing member (e.g., a coil spring 48 in the examples ofFIGS. 6 and 7 ) biases the catch element into engagement with the deck40 to secure the deck 40 to the platform and to prevent the deck 40 fromlifting off the support surface 22 a. The spring 48 bears at one end onthe inside of the side rail 22 and at the other end on a pin 44 b. Thespring can be ground and closed to keep the starting coil at top fromaccidentally threading itself up through smaller hole 23 b in the slot23 when the latch is installed.

FIG. 13 is a perspective illustrating how a latch 42 is installed. Notools are required to remove and install the latch. The latch 42 isinstalled by inserting it at an angle through vertically aligned upperand lower slots 23 as shown in FIG. 8 and then sliding the upper end ofthe latch 42 along the upper slot 23. The shaft 44 is inserted at anangle through the large hole in the upper slot 23, which is sized toallow the shaft 44 and spring 48 to pass through the slot 23, with thelower end passing through the smaller hole in the lower slot 23. Afterthe latch 42 is inserted at an angle, the latch 42 is rotated to theposition shown in FIG. 4 so that the roll pin 44 b in the lower end ofthe shaft 44 prevents withdrawal of the latch 42. The latch 42 is pushedup slightly to compress the spring 48. The roll pin 44 b in the lowerend of the shaft 44 limits the upward movement of the latch 42 but thelocation should provide enough room to align the reduced diametersection 44 a with the upper slot 23. When the reduced diameter section44 a is aligned with the upper slot 23, the reduced diameter section 44a can slide along the narrow section of the slot 23 until the shaft 42is vertically aligned in the smaller set of holes in the slots 23. Inthis way, the upper end 44 d of the shaft 44 is moved away from thelarger hole 23 c of the upper slot 22 c over toward the smaller hole 23b of the upper slot 22 c, while the lower end 44 e of the shaft remainsin the smaller hole 23 b of the lower slot 22 c. When the forcecompressing the spring 48 is removed, the spring 48 pushes the catchelement 46 down to engage the detents 46 a of the catch element 46 inthe slots 23 to prevent rotation of the latch 42.

To install the deck 40, the latch 42 is pushed up slightly to rotate thelatch 42 so that the flat side of the catch element 46 faces the deck 40as shown In FIG. 14A. Once the deck 40 is put into place, the latch 42is rotated 180 degrees so that the curved side extends over and engagesthe top of the deck 40 as shown in FIG. 14B. Even if the latch 42 isaccidentally kicked and rotated, the deck 40 will be held in placeunless the latch is rotated a full 180 degrees, thus providing a higherdegree of safety than conventional designs currently in use. The shapeof the catch element 46 reduces the risk of kicking and accidentallydisengaging the catch element 46. Additionally, recess or countersink 40b is provided in the top surface of the deck 40 into which the catchelement 46 seats so that the catch element 46 is flush with or below thetop surface of the deck 40. Providing a recess 40 b in the deck 40reduces the tripping hazard and further reduces the likelihood that thecatch element 46 will be accidentally kicked and disengaged.

Additional details of the second embodiment of the multifunctionscaffold are described in co-pending U.S. patent application Ser. No.17/716,781 filed on Apr. 8, 2022, which is incorporated herein in itsentirety by reference.

What is claimed is:
 1. A scaffold comprising: first and second ladderframes; an adjustable height platform configured to be supported betweenthe first and second ladder frames at a user selected height in anadjustment range, the adjustable height platform comprising: a pair ofspaced-apart side rails extending between the ladder frames; a decksupported on opposing sides by the side rails, the deck including atleast one recess in a top surface of the deck adjacent one of the sidesof the deck; and at least one latch rotatably mounted to each side railand including a catch element for engagement with the recess in the topsurface of the deck to secure the deck on the side rails; and whereinthe latch is movable between a disengaged position allowing the deck tobe installed or removed from the side rials and an engaged position inwhich the catch element extends over a top surface of the deck andengages with a respective one of the recesses in the deck so that thecatch element is flush with or below the surface of the deck.
 2. Thescaffold of claim 1, wherein the adjustable height platform comprises apair of latches mounted to each side rail, and a pair or correspondingrecesses adjacent each of the opposing sides of the deck for engagementwith respective latches.
 3. The scaffold of claim 1, wherein each siderail is configured to be supported between the ladder frames in firstand second orientations, and wherein the side rail comprises first andsecond support surfaces for supporting a deck of the scaffold in thefirst and second orientations respectively
 4. The scaffold of claim 3,further comprising a first set of latches for holding the deck in placeagainst the first support surfaces of the side rails in the firstorientation and a second set of latches for holding the deck in placeagainst the second support surfaces of the side rails in the secondorientation.
 5. The scaffold of claim 4, wherein: the first set oflatches and second of latches are mounted internally in the side rails;the first set of latches extend vertically through the first supportsurface of the side rails when the side rails are in the firstorientation; and the second set of latches extend vertically through thesecond support surfaces of the side rails when the side rails are in thesecond orientation:
 6. The scaffold of claim of claim 5, wherein: thedeck includes a plurality of elongated slots adjacent the opposing edgesof the deck; the first set of latches extend through the elongated slotsin the deck to engage an upper surface of the deck when the side railsare in the first orientation; and the second set of latches extendthrough the elongated slots in the deck to engage the upper surface ofthe deck when the side rails are in the first orientation.
 7. Thescaffold of claim 6, wherein the latches in the first and second sets oflatches are spring-biased to press the deck downward against the firstor second support surface respectively.
 8. The scaffold of claim 3,wherein each side rail further includes first and second verticallyaligned slots formed in respective opposing surfaces of the side rails.9. The scaffold of claim 8, wherein each latch further comprises a shaftconnected to the catch element, and a biasing member to bias the catchelement into engagement with the deck and secure the deck against one ofthe support surfaces of a respective one of the side rails depending onthe orientation, wherein each latch is configured to be removablyengaged with the first and second slots of a respective one of the siderails in both the first and second orientations.
 10. The side railassembly of claim 9, wherein each slot comprises: a channel extendingalong a longitudinal axis of the side rail; a first hole that is widerthan the channel; and a second hole that is spaced away from, and widerthan, the first hole; wherein both the first hole and the second holeintersect the channel.
 11. The side rail assembly of claim 10, wherein,a lower end of the shaft is configured to engage with the first hole ina lower one of the slots, and wherein an upper end of the shaft isconfigured to engage with the first hole in an upper one of the slots.12. The side rail assembly of claim 11, wherein the latch furthercomprises, toward the lower end of the shaft, a protrusion that is widerthan the first hole of each of the slots.
 13. The side rail assembly ofclaim 11, wherein the biasing member comprises a coil spring disposedaround the shaft of the latch and is arranged to bias the latch in adownward direction when the latch is installed in the side rail.
 14. Theside rail assembly of claim 13, wherein the latch further comprises,between the lower and upper ends of the shaft, a protrusion to which thecoil spring is attached.
 15. The side rail assembly of claim 13, whereinthe coil spring coils around the shaft in a diameter wider than thefirst hole of each of the slots.
 16. The side rail assembly of claim 13,wherein the second hole is configured to allow insertion of the latchand coil spring through the second hole in the upper slot duringinstallation of the latch into the side rail.
 17. The side rail assemblyof claim 16, wherein the latch includes a reduced diameter sectionspaced from the catch element, the reduced diameter section beingconfigured to slide within the channel during installation of the latchinto the side rail.
 18. The side rail assembly of claim 11, wherein theshaft comprises sections above and below the reduced diameter sectionthat are wider than the channel of each slot and narrower than the firstand second holes of each slot.
 19. The side rail assembly of claim 10,wherein the catch element includes at least one detent configured toengage within the channel of an upper one or the slots when the latch isinstalled in the side rail.
 20. The side rail assembly of claim 13,wherein: the catch element includes a flat section; and the detent isconfigured to engage the channel with the flat of the catch element in afirst position facing towards the deck and a second position facing awayfrom the deck.